High-speed circuit interrupter



July 7, 1931. J. B. M NEILL 1,813,181

HIGH SPEED CIRCUIT INTERRUPTER Original Filed June 7, 1926 l3 /5 WITNESSES: INVENTOR a ayw/g/ I JahnBMac/Vefi/ (ATTORNEY v Patented July 7, 1931 STATES JOHN 353. MACNEILL, OF WILKINSBURG, PENNSYLVANIA, ASBIGNOR TO WESTINGHOUSE ELECTREC 6o MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA HIGH-SPEED CEBGUIT INTERBUPTEB application filed June 7, 1926, Serial No. 114,045. Renewed November 8, 1930,

My invention relates to electrical protective apparatus and more particularly to'highspeed circuit interrupters. v

@ne object of my invention is to provide a highspced circuit interrupter that shall be responsive to the rate of change of an electrical current traversing it.

Another object of my invention is to provide a circuit interrupter that shall be held in its circuit-closing position only by the magetic attraction between the core and armature of an electro-magnet.

A further object of my invention is to provide a high-speed circuit interrupter, the holding cl-ectromagnet of which shall be moved into the circuit-opening position of its armature member after which the holding electro-magnet and armature are moved to their circuit-closing positions.

ln constructing high-speed circ'uit interrup ters that shall be capable of opening a power circuit in short intervals of time, of the order of ten one-thousandths (.010) of a second, it has been found most expedient to eliminate all mechanical latches and to depend solely upon magnetic forces in order to release the actuating members for the relatively movable contact members. The holding electro-magnets for such high-speed circuit interrupters are characterized by having portions o'fthe load currents traverse conductors placed in air-gapsin the core structures, such that, when abnormal cur- T rents traverse the conductors, the total amounts cs5 iiux traversing the cores are not decreased, but are merely shunted from one air-gap to another, whereby the armatures are released and moved to their open-circuit positions by powerful accelerating springs.

order to close such a circuit interrupter I propose to move the holding electro-magnet, its entirety, to a position where it may seize its armature, after which it and the actuating means are moved into their circuitclosing positions. The armature comprises a portion of the actuating means for the relatively movable contact members.

In order to accomplish the foregoing results, I suspend the holding electro-magnet from a second electro-magnet so that, when the second electro-magnet is deenergized, the holding electro-magnet is permitted to move downwardly and engage its armature. After the second electro-magnet is re-energized, it moves the holding electro-magnet, its armature and the contact-actuating means upwardly to their several circuit-closing positions.

My circuit interrupter differs from any other high-speed circuit interrupter of which I am aware in that the holding electric-mag net is moved to engage its armature instead of the armature being moved to engage the holding electro-magnet.

In the accompanying drawings,

Figure 1 is a diagrammatic view of circuits and apparatus showing my circuit interrupter in its circuit-closing position.

Fig. 2 is a diagrammatic view of the circuit interrupter in an intermediate circuitopening position, and

Fig. 3 is a similar view of the circuit interrupter in its final circuit-opening position.

My invention comprises, in general, a circuit interrupter 1 having a stationary con tact member 2, a movable contact member 3 and an actuating lever i, therefor, that is attached to an armature 5 of a holding electromagnet 6, both of which are biased to their lower, or circuit-opening posit-ions by a coil spring 7 and an electro-magnet 8 for controlling the position of the electro-magnet 6.

The actuating lever 4 is of'insulating material and carries the contact member 3 to which is secured one of the conductors of an electrical circuit 11 with which the circuit interrupter 1 is associated. A pilot switch 12 is dependent from the lever 4 and bridges a pair of stationary contact members 13 when the'circuit interrupter is in its open position.-

The coil spring 7 is connected to a pintle 14 positioned midway of the lever 4. The pintle 14 is also connected, by a link 15, to the armature 5. The other end of the lever 4.. is connected. to a resilient mounting 16 that serves to bias the lever 4 in a counter-clockwise direction about the pintle 14 when the circuit interrupter is in its circuit-closing position r. thereby keepingthe contact members 2 and under spring pressure.- i

" Eils 18is determined {by the value of'the resistor 38. However, whenthe actuating lever 4 moves to its open position, the pilot The holding electro-magnet'fi comprises a 'U-shape core 17 on the legs of which are mounted a pair of coils 18 that are accuinulatively wound to produce an electric flux that traverses an air-gap 19 in the core 17 adjacent to the armature 5. The air-gap 19 is of peculiar configuration- The outer'wallsof the air-gap 19 adjacent to the area of engagement with the armature 5 are relatively close to each other. From the outer orificeof the air-gap 19 the walls diverge and then abrupt- 1y terminate in shoulders 21 that aresepafrom the outer ortion of the core6 to the shoulders 21 an the air-gap thereby releasing the armature 5.

The holding electro-magnet 6 is connected by a link .24 to an armature 25 of the electromagnet 8. A cross-bar 26, attached to the latter moves to itsiopen position, thereby recult-opening and releases t e latch 31 from the pui 27.

" current to -th e circuit 11' through Qationary link 24, supports a pin 27 at one end and, at its other end, apilot switch 28 that cooperates with" a contact member 29. The pin '27 '00- operates with a latch 31 .that is actuated,

through a rod 32 from a pin .33. The pin 33 is engaged by the operating lever 4 when the leasing the latch 31 from the-pin 27,

Referring toFig. 1, a generator 35 supplies and .movable contact members "2 and 3, the

' conductor 23 and a reactance 36the latter being in parallel circuit with the conductor 1 9.23: The reactance 36 is so proportioned that,

' upon the occurrence of slow changes in the current traversing the circuit 11, the relative proportions ofthe current traversing the com ductor 23 and the reactance 36 does not'vary. However, upon the occurrence of sudden changes in the value of thecurrent traversing the circuit 11, the pro rtion of that 6urrent traversing the con uctor 23 becomes, ,materially-greater than thattraversing the reactanc'e36, with th result that the armature5 is' released. The operation of the reactance .36 andfth'e conductor. 23 depends upon the rate of ohangeof current travers- 'ing' the circuit 11) and, accordingly, the circuit interrupter 1 operates. inanticipation ofsudden overload or short-circuit currents.

The coils 18of the holding electro magnet 6 are energized through a hand switch-37 and aso 38 that is connected in p'arallel circuit to the stationary contact members 13, whereby the amount of current traversing the tro-inagnetfi for its r lease.

is controlled by a hand switch 39 and a. time rela 41 having a bridging member 42 and stationary contact member 43. the pilot switch 28, that completes a circuit beis energized to complete a circuit throughthe brid ing member 42, the stationary contactfl mem I rs 43 and the electro-magnet 8. v

A resistor 44 is placed in parallel circuit,

with the electro-magnet' 8 to provide a surge discharge path therefor.

Assuming the circuit interru terlto theclosed position shown in ig. 1, and a condition of short-circuit to have occurred, in the circuit '11, the -current-travers ing the I conductor 23'. is suddenly greatly increased,

with the result that the flux traversing the core 17 is caused to bridge the air-gapo22, rather than outer portions of the air-gap 19 and the armature 5, with the result that the armature5 is released. pon the relea'se of opening position. The cirduit opening movetween the stationary contact members 29 and the switch 39 isclosed, the coil of the relay 41 o the"armature 5, the spring7 contracts to'ac celerate the lever 4 into its-lower or circuits r ment ,ofthe actuatinglever 4 is independent of airy mechanical latches and de nds en-[ tirely upon the-electrical action 0 the-elecv, I

lever 4 reaches oslti'on it strikes the "When the a'ctuatin A The armature 25 of the electro-ma'gnet 8 and its cir 3 the electromagnet 6 then drop down'to the position shown in Fig. 3 where the core 18 again enga the armature 5. At the same time, the pi ot switchf28comp1etes the circuit between the stationary contact members 29.

' Y In order'to re-close the circuit interrupter,

the coils 18 are energized through the switchterrupter 1. owever, the coils 18 are traversedby a greater current when the circuit interrupter 1 is in its open position by reason .37 if they have not remained energized durthe openin movement of the circuit in- H seize the armature '5'than is'necessary to retain it in its closed or seized osi'tion.

The switch 39 is then mampulatcd to close gr-circuit through the coil of relay 41, the'stat1on ary contact members 29 and the brid 'ng member 28. Upon the energization o the relay 41, the circuit between the stationary .actuating l ever' 4 against the. tension of the spring 7.

When the bar-26 has raised in enough contact members 43 is closed by the bridging nausea to cause the pin 27 to engage the latch 31, the circuit for the relay 41 is interrupted by the pilot switch 28, and the shunt circuit around the. resistor 38 is opened by the switch 12.

- After an interval of time corresponding to the setting of the relay 41, the circuit'of the ilantro-magnet 8 is interrupted between the stationary members 43, and the latter becomes deenergized. The operator should then open the switch 39 in order to prevent the circuit I interrupter 1 from closing automatically afterits next circuit-opening operation. The coils 18 remain energized while the circuit interrupter 1 is closed in order to keep the actuating lever 4 in its upper, or circuitclosing', position.

Accordingly, I have provided a circuit interrupter for high-speed operation in which the holding electro-magnet is moved to the circuit-opening position of an actuating lever, that lever is then magnetically seized, and the holding electro-magnet and lever are returned to their circuit-closing positions by the action oi a second electro-magnet. Since the holding electro-magnet and the actuating lever are held in engagement only by magnetic forces, it is possible to cause their separation in a much shorter time than is required when mechanical latches must be ac-- celerated before the circuit-opening oper-' ation takes place. The resilient mounting of the actuating lever insures that the contact members are held in firm engagement when closed.

It is to be understood that various changes in the arrangement, connection, shape and outline of the component parts of my invention may be made within the scope of the appended claims.

I claim as my invention:

1. In a high-speed circuit interrupter, a pair of relatively movable contact members, actuating means for the contact members biased to its circuit-opening position, and

magnetic holding means for the actuating means adapted to be moved to the circuitopening position of, and engage, the actuating means and then bemoved so as to move the actuating means to its circuit-closing position.

2. In a high-speed circuit interrupter, a pair of relatively movable contact'members, actuating means for the contact members biased to its circuit-opening position, and a holding ,electro-magnet for the actuating means adapted to be moved to the circuitopening position of, and engage, the actuating means and then be moved so as to move the actuating means to its circuit-closing position.

3. In a high speed circuit interrupter, apair of relativelymovable contact members, actuating means for the contact members biased to its circuit-opening position, and an electrical holding means for the actuating means adapted to be moved to the c rcuitopening position of, and engage, the actuatlng means and then be moved so as tomove the actuating means to its circuit-closing po- I sition.

4. In a high-speed circuit interrupter, a pair of relatively movable contact members, actuating means for the contact members biased to its circuit-opening position, holding means for the actuating means, means for moving the holding means into the circuit-opening position of the actuating means and means for moving the holding means into their circuit-closing positions.

5. In a high-speed circuit interrupter, a pair of relatively movable contact members, actuating means for the contact members, biased to its circuit-opening position, a holding el'ectro-magnet for the actuating means, means for moving the holding electro-magnet into the circuit-opening position of the actuating means and means for moving the holding electro-lnagnet and the actuating means into their circuit-closing positions.

6. In a high-speed circuit interrupter, a pair of relatively movable contact members, actuating means for the contact members biased to its circuit-opening position, a holding electro-magnet for the actuating means, means for moving the holding electro-magnet intothe circuit-opening position of the actuating means and an electro magnet for moving the actuating means and the holding electro-magnet into their circuit-closing positions.

7. In a high-speed. circuit interrupter a pair of relatively movabl contact members, and actuating means therefor, a magnetic holding means for the actuating means and an electro-magnet for bodily moving the magnetic holding means.

8.-In a high-speed circuit interrupter, a pair of relatively movable contact members, an actuating means therefor, an electromagnetic holding means for the act uating'means and means for moving the entire said electromagnetic holding means. I

9. In a high-speed circuit interrupter, a pair of relatively movable contact members, an actuating means therefor, a holding electro-magnet for the actuating means and an electro-magnet for moving the entire holding electro-magnet.

10. In a high speed circuit interrupter a pair of relatively movablecontact members, an actuating means therefor,,a holding electro-magnet for the actuating means and an biased to its circuit-opening position, a holdelectro-magnet and the held actuating means.

11. In a high-speed circuit interrupter, a pair of relatively movable contact members, an actuating means therefor biased to the circuit-opening position and comprising an armature, a holding electro-magnet for controlling the armature,,and a second elecc magnet to follow thearmature' member and l tro-mag net for controlling the position of the holdin electro-magnet.

;magnet for moving the holding electro-ina gnet armature, a hol 12. n a' bi h-s'peed circuit interrupter, a pair of relatively movable contact members, an actuating means therefor biased to its circuit-opening (positiontand comprising an trolling the armature,-and a second electroand the armature from the circuit-interrupting position of the'latter to its circuit-closing position;

13. In a high-speed circuit interrupter, a pair of relatively movable contact members,

an actuating means therefor biased'to its' circuit-opening position and comprising an armature, a holding ele'ctro-magnet-for' controlling the armature, and asecond electromagnet which, when de-energized, permits the holding'electro-magnet to move to the circuit-opening position of the armature and,

I when subsequently ener ized, moves the hold- .ing electr'o-magnet an and actuating means-therefor biased to its armature, a hol to their circuit-closing positions.

14. In a high-speed circuitinterrupter, a. 7

pair of relatively movable contact members,

circuit-opening (position and comprising an ng electro-magnet adapted toretain the armature under normal conditions and to release it under abnormal conditions whereupon the actuating means moves to its circult-openmg posltlon, and a second electro-magnet to permit the holding electro to return it to its circuit-closing position.

In: testimony whereof, -I have hereunto subscribed my 1926. Y e

' JOHN. B. MAONEILL.

lng electro-magnet for 0011- attracted armature .name this 2nd day of June, 

